Search

The objective this paper was to quantify the hourly variability of CO 2 fluxes in the year of the El Nino, in 2015, in a tropical rain forest in the Western Amazon. Data of CO 2 fluxes collected at 63.5 m height in a tower of the Large-Scale Biosphere–Atmosphere Experiment in Amazonia in the Jaru Biological Reserve, composed of the Open Ombrophilous forest, were analyzed. Data from the dry-wet period were used, which by convention, the negative and positive values indicate absorption and emission of CO 2 , respectively. The CO 2 uptake in the forest had higher levels between 9:30 a.m. and 4:00 p.m., with mean values between -19 and -13 μmol m -2 s -1 , however the peak absorption occurs at 1:00 p.m. with -30 μmol m -2 s -1 , considering that at this time the sun's rays are most intense. In average, the Rebio Jaru absorbs more than the areas of the transition Amazonia-Cerrado, indicating that the physiological activities in Ombrophilous forest require a greater amount of carbon. The average daily behavior of CO 2 fluxes showed higher concentrations of absorption during the day than emissions overnight, behaving as a carbon sink, corroborating the importance of the forest in assimilation of the atmospheric carbon.